Oxygen controlled PVD aluminum nitride buffer for gallium nitride-based optoelectronic and electronic devices

Abstract

Oxygen controlled PVD AlN buffers for GaN-based optoelectronic and electronic devices is described. Methods of forming a PVD AlN buffer for GaN-based optoelectronic and electronic devices in an oxygen controlled manner are also described. In an example, a method of forming an aluminum nitride (AlN) buffer layer for GaN-based optoelectronic or electronic devices involves reactive sputtering an AlN layer above a substrate, the reactive sputtering involving reacting an aluminum-containing target housed in a physical vapor deposition (PVD) chamber with a nitrogen-containing gas or a plasma based on a nitrogen-containing gas. The method further involves incorporating oxygen into the AlN layer.

What is claimed is: 
     
       1. A material stack for GaN-based optoelectronic or electronic devices, the material stack comprising:
 a substrate selected from the group consisting of sapphire, Si, SiC, Si on diamond, ZnO, LiAlO 2 , MgO, GaAs, Copper and W; 
 an aluminum nitride (AlN) buffer layer disposed directly on the substrate, the AlN layer comprising a concentration of oxygen between 1E18 and 1E23 cm −3 , wherein a portion of the oxygen is included at an AlN/substrate interface, and wherein the AlN buffer layer has a thickness of approximately 20 nanometers; and 
 a high quality GaN layer disposed on the AlN buffer layer, the high quality GaN layer having XRD (002) FWHM<100 arcsec and XRD (102) FWHM<150 arcsec. 
 
     
     
       2. The material stack of  claim 1 , wherein another portion of the oxygen is included at an outermost surface of the MN buffer layer. 
     
     
       3. The material stack of  claim 1 , wherein the substrate is a sapphire substrate. 
     
     
       4. The material stack of  claim 1 , wherein the substrate is a Si substrate. 
     
     
       5. The material stack of  claim 1 , wherein the substrate is a SiC substrate. 
     
     
       6. The material stack of  claim 1 , wherein the substrate is a ZnO substrate. 
     
     
       7. The material stack of  claim 1 , wherein the substrate is a LiAlO 2  substrate. 
     
     
       8. The material stack of  claim 1 , wherein the substrate is a GaAs substrate. 
     
     
       9. A light-emitting diode (LED) device, comprising:
 a substrate selected from the group consisting of sapphire, Si, SiC, Si on diamond, ZnO, LiAlO 2 , MgO, GaAs, Copper and W; 
 an aluminum nitride (AlN) buffer layer disposed directly on the substrate, the AlN layer comprising a concentration of oxygen between 1E18 and 1E23 cm −3 , wherein a portion of the oxygen is included at an AlN/substrate interface, and wherein the AlN buffer layer has a thickness of approximately 20 nanometers; and 
 a high quality GaN layer disposed on the AlN buffer layer, the high quality GaN layer having XRD (002) FWHM<100 arcsec and XRD (102) FWHM<150 arcsec. 
 
     
     
       10. The LED device of  claim 9 , wherein another portion of the oxygen is included at an outermost surface of the AlN buffer layer. 
     
     
       11. The LED device of  claim 9 , wherein the substrate is a sapphire substrate. 
     
     
       12. The LED device of  claim 9 , wherein the substrate is a Si substrate. 
     
     
       13. The LED device of  claim 9 , wherein the substrate is a SiC substrate. 
     
     
       14. The LED device of  claim 9 , wherein the substrate is a ZnO substrate. 
     
     
       15. The LED device of  claim 9 , wherein the substrate is a LiAlO 2  substrate. 
     
     
       16. The LED device of  claim 9 , wherein the substrate is a GaAs substrate. 
     
     
       17. A material stack for GaN-based optoelectronic or electronic devices, the material stack comprising:
 a substrate selected from the group consisting of sapphire, Si, SiC, Si on diamond, ZnO, LiAlO 2 , MgO, GaAs, Copper and W; 
 an aluminum nitride (AlN) buffer layer disposed directly on the substrate, the AlN layer comprising a concentration of oxygen between 1E18 and 1E23 cm −3 , wherein a portion of the oxygen is included at an AlN/substrate interface, wherein the substrate is a Si on diamond substrate, and wherein the AlN buffer layer has a thickness of approximately 20 nanometers; and 
 a gallium nitride (GaN) layer disposed on the AlN buffer layer. 
 
     
     
       18. A light-emitting diode (LED) device, comprising:
 a substrate selected from the group consisting of sapphire, Si, SiC, Si on diamond, ZnO, LiAlO 2 , MgO, GaAs, Copper and W; 
 an aluminum nitride (AlN) buffer layer disposed directly on the substrate, the AlN layer comprising a concentration of oxygen between 1E18 and 1E23 cm −3 , wherein a portion of the oxygen is included at an AlN/substrate interface, wherein the substrate is a Si on diamond substrate, and wherein the AlN buffer layer has a thickness of approximately 20 nanometers; and 
 a gallium nitride (GaN) layer disposed on the AlN buffer layer. 
 
     
     
       19. A material stack for GaN-based optoelectronic or electronic devices, the material stack comprising:
 a substrate; 
 an aluminum nitride (AlN) buffer layer disposed directly on the substrate, the AlN layer comprising a concentration of oxygen between 1E18 and 1E23 cm −3 , wherein a portion of the oxygen is included at an AlN/substrate interface, and wherein the AlN buffer layer has a thickness of approximately 20 nanometers; and 
 a high quality GaN layer disposed on the AlN buffer layer. 
 
     
     
       20. The material stack of  claim 19 , wherein another portion of the oxygen is included at an outermost surface of the AlN buffer layer.